Question

While 75-kg Anthony roller skates at 3 m/s, 60-kg Sue jumps into his arms with a velocity of 5 m/s. How fast does the pair go together?

Velocity: m/s

Direction:

Answer 1

Apply conservation of linear momentum

$\\ \rm\Rrightarrow m1v1+m2v2=(m1+m2)V3$

$\\ \rm\Rrightarrow 75(3)+60(5)=(75+60)V3$

$\\ \rm\Rrightarrow 225+300=135v3$

$\\ \rm\Rrightarrow 525=135v3$

$\\ \rm\Rrightarrow V3=3.89m/s$